Stamped metal fluid heater



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May 3, 1938. f A. P. BALL ET Al. v 2,116,298

STAMPED METAL FLUID HEATER Filed Oct. 10,-1935 2 Sheets-Sheet 1 May 3, 1938.

A. P. BALL ET AL STAMPED METAL FLUID HEATER Fiied ooi.

10, 1935 2 Sheets-Sheet 2- INVENYTORS. Hler 7. aZZ

Patented May 3, 1938 STAMIED- METAL FLUID HEATER Albert I?. Ball and William lvlarshall, Detroit,

Mich., assignors to Briggs Manufacturing Company, Detroit, Mich., a corporation of Michigan Application October l0, 1935, Serial No. 44,406 13 claims. (o1. 122-156) The present invention relates to a fluid heater having a fluid-heatingportion preferably formed from sheetmetal stampings, the heater being particularly but not exclusively adapted for use with a fluid storage tank of conventional design and is of a construction which may be used satisfactorily in `installations for heating'water for domestic uses. l

It is an object of the present invention to provide a fluid heater which has a high efliciency in heating fluids with which it is used, the heater being of a compact size and of economical construction, being of a construction which may be formed largely of sheet metal stampings.

l5 It is a further object of the invention to Dro- Vide a fluid heater which is so Constructed of sheet metal stampings as to provide a substan-` tially uniform circulation of the fluid at all points of contact with the heated surface and thus to increase the service life ofsuch heater and to effect the substantial elimination of depositsv in the lluid chamber and the consequent burning out of the heated wall of the chamber.

Fluid heaters intended for similar uses heretofore known in the art have been provided'with metallic tubular coils throughwhich was circulated the fluid to be heated. The coils were commonly of l a relatively small cross-sectional area which remained uniform throughout the length of the coil so that a constant velocity would normally be imparted to the fluid flowing through the coils. When,fhowever, heat Was supplied as in conventional practice to the lower portions of the coils, the fluid in the coils at that point was heated to a greater degree than the fluid in the upper portions of the coils and the velocity of the fluid passing through the coils was greatly increased so that the rate of ow of fluid through the coils at points removed from the point of application of greatest heat wasv so rapid as to prevent substantially uniform heating of the fluid while in the heater. In additionl to the high cost incident to-the formation of heating coils used in such heaters, it is well.known that the coils become lined with various mineral substances carried by the fluid to be heated. For example, in the case of hot water heaters it is common to find upon opening such coils a relatively thick coating of mineral carbonates and the like on coils at the points of greatest application of heat to the fluid. This coating of mineral carbonates not only reduces the efficiency of the heater, but also impairs the free Circulation of fluid through the heater and,` if-allowed to ac- `l cumulate over a` period of time,results in either plugging the c-oils or causing a breakage of the coils by reason of the high pressures built up therein by the fluid which cannot circulate freely through the coils.

The foregoing defects of prior existing structures are overcome by the present invention which in one preferred embodiment thereof is shown in the accompanying drawings.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

Fig. l is a longitudinal sectional View showing a heater of our present invention, showing a fragment of a stack pipe connected thereto.

Fig. 2 is a sectional view taken substantially on the line 2-2 of Fig` 1 in the direction of the arrows. v Y

Fig. 3 is a sectional View taken substantially on the line 3"?! of Fig. 1 in the direction of the arrows,

Fig. 4 is a sectional View taken substantially on the line 4 4 of Fig. 1 in the direction of the arrows. l

Fig. 5 is a sectional view taken substantially cn the line 5-5 of Fig. 1 in the direction of the arrows. l

Fig. 6 is a sectional view taken substantiallyon the line 6 6 of Fig. 1 in the `direction of the arrows.

Before explaining in detail the present invention it is to be understood that the invention is not limited in its application tothe details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation, and it ls not intended to limit the invention claimed herein beyond the requirements of the prior art.

Referring to the drawings, particularly to Fig. 1, the huid heater of the present invention comprises a fluid jacket formed by joining the outer shell lll with an inner shell `ll so as to provide a fluid receiving chamber l2 therebetween. As shown in Fig. l, the fluid jacket on the exterior is generally conical in shape, but the inner plate I l is formed so as to determine the size and shape of the fluid receiving chamber I2 and is secured as by welding to the outer wall I0 adjacent each. of the ends thereof. J

The outer jacket I0 and the inner jacket II are both formed preferably from flat sheet metal stock which is formed as by conventional stamping operations. As shown in Figs. 3, 4 and 5, the

outer shell I0 is formed to provide an outer cas ing which tapers substantially uniformly throughout its length. The outer shell IU is bent to provide longitudinally extending lugs I3 which project outwardly from the surface of the outer shell IIJ. The inner shell II is formed to provide a series of longitudinally extending corrugations I4 at portions thereof where the greatest amount of heat is supplied to the shell I I. The corruga tions may be formed in the sheet metal as by conventional rolling or stamping operations. The inner shell II may be formed of any preferred type of sheet metal which has a relatively high efficiency in the transfer of heat from the interior of the heater to the fluid chamber I2 and which either is substantially non-corrosive with the fluid passing through the chamber or which has been treated so as to become substantially noncorrosive.

The provision of the corrugations I4 increases the surface area of the inner shell II which will come in contact with the heat and also in contact with the fluid medium circulating through the chamber I2. The inner chamber II is provided with longitudinally extending edges I5 which are turned and project outwardly to a point of contact with the flanges I3 provided on the outer shell I0. The flanges I3 and the edges I5 are secured as by welding. This construction provides a baiile I6 which extends longitudinally throughout the length of the uid chamber I2 so that the fluid in the chamber I2 will be required to rise as a column instead of circulating as a flowing stream. This increases the efficiency of the heater in that it provides a more constant` body of fluid to be heated than where the fluid is permitted to circulate as a flowing stream around the heating chamber.

At the points where the least amount of heat is supplied to the inner shell II, the shell is formed, as shown in Fig. 3, without the longitudinal corrugations I4 in the surface thereof. The interior of the heater is thus formed to provide a central flue 20 surrounded by the inner shell I I and through which the heated gaseous products of combustion are conveyed to the stack 2I. In order to increase the surface area of contact of the heated gaseous products of combustion with the inner shell II, a series of bales 22 are interposed in the flue 20. As shown in Figs. 1 and 2, each of the baille members 22 is secured to a depending rod 23 which is secured to a cross bar 24 placed adjacent the top of the shells IIJ and II. Each of the baffles 22, as shown in Figs. 1, 2, 3 and 4, comprises a circular disc 25 to which lugs 2E are secured which extend outwardly therefrom to contact with the inner shell II. This contact assists in maintaining the baiiles 22 in the central portion of the ilue 2D and also serves to increase the amount of heat conveyed to the shell I I. Each of the circular portions 25 of the bailles 22 is stamped or otherwise formed to provide a conical surface 2'I having its apex lying in a line extending through the rod 23 and pointing downwardly toward the lower portion of the flue 20. The provision of the conical surface 2'I on each of the bafes 22 serve to deflect outwardly toward the inner shell I I the heated gaseous products of combustion which travel upwardly through the ilue 20.

The particular form of the fluid heater herein shown may be varied in its construction in such a manner as to accommodate various types of heating apparatus. One preferred type of heating apparatus which is shown herein utilizes cornbustible gas as the fuel and admixes such gas with air and is distributed through a burner which is provided with a series of jets 3|. When, as here shown, the heater of the present invention is adapted to this type of heating apparatus, a stamped shell is provided to form a chamber in which the burner 3U is placed. One form of such shell is shown in Fig; 1 and comprises an annular band or collar 32, the upper edge of which telescopes inside the lower end of the inner shell II.

In order to permit access to the interior of the chamber surrounded by the collar 32, a portion of the collar 32 is cut away and a hinged door 33 is provided. As shown in Fig. 6, the hinged door 33 may be formed from sheet metal and pivoted about a rod 34 which is secured in the collar 32 adjacent one vertical edge of the opening provided therein.. A door 33 may be malntained in a closed position by a friction catch utilizing the resiliency of the metal used in forming the door. Such a catch may be formed by the provision of a depressed portion 35 on the inner surface of the door 33 which engages an outwardly extending member 3B formed in the collar 32 at a point adjacent one vertical edge of the opening provided therein. In order to facilitate the opening and closing of the door 33, an extending handle 31 may be provided thereon.

The burner 30 may be maintained in the chamber by means of a burner supporting base member 4D provided with upwardly extending end portions 4I which telescope inside the lower edge of the collar 32 and are secured thereto as by Welding or the like. The base member is provided with tapering sides 42 and a flat portion 43 in which a burner receiving opening 44 is provided (see Fig. 6). The burner 30 is supported on a stem 45 on which an annular shoulder 46 is provided. The stem 45 is also provided with a screw-threaded portion 4'I. The stem 45 extends upwardly through the opening 44 and is clamped thereon as by nuts 48 which engage with the screw-threaded portion 4'I on each side of the flat portion 43 of the supporting member 4I). The stem 45 is connected with a source of gas supply (not shown) and is provided with an interior conduit 49 for supplying gas to the interior of the burner 30.

Fluid to be heated is supplied to the fluid chamber I2 through an intake coupling 50 which is connected to the outer shell I0 at a point adjacent the lower end thereof. 'I'he fluid then passes to the chamber I2 but is prevented from flowing as a stream therein by reason of the longitudinal baille I6 and the fluid rises as a column in the chamber I2 and is discharged through the discharge coupling 5I which is secured to the outer shell I0 at a pointadjacent the upper end'I thereof.

In order to insure substantially uniform heating of the column of fluid in the chamber I2, the construction herein shown provides an interior chamber I2 of gradually decreasing capacity so that the greatest volume of fluid is in the lower part of the chamber and comes in contact with the greatest amount of heat. As the fluidY in the lower portion of the chamber is heated and rises in the chamber I2, it moves toward the discharge coupling 5I in the form of a gradually thinning annular band which absorbs the heat which passes through the inner shell Il at the point adjacent the top thereof. The heat at this point, however, is of considerably less intensity than the heat supplied at the lower end of the chamber as the heated products of combustion have been cooled by repeated contacts with the heat contacting wall of the inner shell l I. It has been found that this construction of the fluid heating chamber I2 is desirable" as it tends to maintain the flow of fluid through the heater at a substantially constant Velocity and thus to provide a substantially uniform transfer of heat from the heated products of combustion to the fluid during its travel through the heating chamber.

What is claimed is:

1. A fluid heater comprising a boiler formed of inner and outer sheet metal stampings having fluid inlet and outlet ports and having a flue extending longitudinally of the interior thereof, said inner stamping providing a flue lining member forming one wall of said boiler and having longitudinal corrugations to increase its surface contact with gases in said flue and the fluid in said boiler, and said inner stamping having a pair of longitudinally extending cooperating flanges projecting outwardly in flatwise abutting relation into contact with and secured to said outer stamping to provide a longitudinal baille for the boiler, and a heating member disposed adjacent said flue and adapted to discharge heated products of combustion therethrough.

2. A fluid heater comprising spaced inner and outer shells secured together to provide a iluid chamber therebetween, a heating member secured adjacent said inner shell, and a fluid inlet and fluid outlet communicating with said chamber, the inner of said shells comprising a sheet metal plate corrugated longitudinally thereof to increase the surface area exposed to Contact With-the fluid in said fluid chamber and folded to provide extending portions attached to said outer shell, thereby to provide a baffle extending longitudinally of said fluid chamber.

3. A fluid heater including spaced inner and outer shells sealed to provide a fluid chamber therebetween, a fluid inlet and fluid outlet communicating with said chamber, the inner of said shells comprising a sheet metal plate corrugated longitudinally thereof to increase the surface area exposed to contact with the fluid and folded to provide extending portions attached to said outer shell to form a baille extending longitudinally of said fluid chamber adapted to break up the fluid stream flowing inwardly into said chamber from said fluid inlet.

ALBERT P. BALL. WILLIAM MARSHALL. 

